Twinkle,
I could see your daughter as a [name]MAGNOLIA[/name] if she were to have red hair and green eyes, and I would call her [name]Maggie[/name]. Should she turn out to be more of a blonde, delicate child, I would call her [name]Lia[/name]. And, if she were a more exotic looking child, with dark hair and green or brown eyes, I might even call her [name]Nola[/name].
I might also name her [name]CASSIA[/name], as it means “cinnamon.” This seems to be the perfect name for a sweet, red-headed little girl with big, beautiful, curious eyes and a penchant for adventure. You could call her [name]Cassie[/name], but I think this would fit more for a blonde than a red-head. I don’t know if it is too hard to pull of, but [name]SiSi[/name] (like Cee Cee) would be cute, too…
Another name I could see for this little girl is HOSANNA, a Greek name meaning “praise!” I think it is unique and sassy, just like I picture your daughter to be, but then it can be brought back to more normalcy with the sweet, delicate nickname, [name]Annie[/name].
Going in a different direction, I can see your daughter, strikingly gorgeous with her red hair and green eyes, being named [name]BELLATRIX[/name]. Yes, the name might be a bit unique, or it might remind some people of [name]Harry[/name] [name]Potter[/name], but I think it is cute. It seems to match this “free spirit” image you have conveyed of a theatrical, inquisitive young girl, and she could be called [name]Belle[/name], [name]Bella[/name], or [name]Trixie[/name]!
On the less unusual side, I could see your daughter being called [name]GLORIA[/name], perhaps with the nickname [name]Glory[/name]. However, I would choose this should your daughter turn out to be a bit more reserved than your description might suggest - a quiet personality with her head in the clouds, perhaps…
Perhaps the most normal name I will suggest for her is [name]STELLA[/name]. [name]Serene[/name] and intelligent, yet confident and witty, this name shines just as much as I imagine your daughter will.
Twinkle, I know from reading your other polls that [name]Dorothea[/name] will likely be the other twin’s name. However, I think that [name]Cassia[/name] and [name]Bellatrix[/name] would make a striking pair. I love Hosanna and [name]Magnolia[/name] together, too, as [name]Annie[/name] and [name]Maggie[/name] are so, so sweet!
Good luck!